Sheet fed rotary printing press with sheet slitting attachment



Oct. 23, 1956 A. G. JAcoBsoN ETAL 2,767,790

SHEET FED ROTARY PRINTING PRESS WITH v SHEET SLITTING ATTACHMENT Flled Aug. 15. 1951 3 Sheets-Sheet 1 CCL 23, 1956 A. G. JAcoBsoN ET AL 2,767,790 SHEET FED ROTARY PRINTING PRESS` WITH SHEET SLITTING ATTACHMENT Filed Aug. l5, 1951 3 Sheets-Sheet 2 Oct. 23;' 1956 A. G. JAcoBsoN ETAL 2,767,790

SHEET FED ROTARY PRINTING PRESS WITH SHEET SLITTING ATTACHMENT 5 Sheets-Sheet 3 Filed Aug. 15. 1951 .FILI

United States Patent O SHEET FED RTARY PRINTING PRESS WITH SHEET SLITTING ATTACHMENT Arthur G. Jacobson, deceased, late of Chicago, Ill., by

' Charles C. Cowell, administrator, Riverside, lll., and Christen R. Kaddeland, Chicago, Ill., assignors to Miehle Printing Press & Manufacturing Company, Chicago, lll., a corporation of Delaware Application August 15, 1951, Serial No.' 241,934

Claims. (Cl. 164-61) This invention pertains to rotary printing presses and is` directed more specifically to the combination of an improved sheet or webl slitting mechanism with such presses.

The slitting device disclosed in this application was designed primarily for sheet fed rotary printing presses. However, it will be apparent that, with but minor modications, the device may also be readily adapted to web fed presses with equally eiiicient results. Preferably, the press is equipped with two rotary sheet transfer members which convey the sheets from the last printing unit of the press to the delivery mechanism, and one of these members also functions as a slitter drum. The slitter unit is so arranged that the actual slitting of a sheet does not begin until all printing on a sheet has been completed.

There are many devices now in use for the purpose of slitting sheets or webs of paper into two or more sections. Most of these devices, however, are designed spe citically for operation on web fed presses and, therefore, cannot be conveniently adapted for the slitting of sheets on sheet fed presses. On the other hand, the slitters that have been developed for sheet fed printing presses are generally unsatisfactory for the simple reason that they are arranged to coact with the impression cylinder of the press to slit the sheets while they are still held by the impression cylinder grippers and while the sheet is still receiving the impression.

When a slitter is arranged to slit sheets on the surface of the impression cylinder, it must of necessity, begin slitting the leading edge of a sheet while the trailing portion thereof is still receiving the impression.) Consequently any distortion of the sheet, or any variation in the tension on the sheet resulting from the action of the slitter, will invariably disturb the register of the print on the trailing portion thereof and render the linished product unacceptable to the trade. Furthermore, it is exceedingly ditiicult to adjust such slitters properly because of the fact that in order to prevent damage to the impression surface of the cylinder, it is necessary to provide on the cylinder, for each slitter, a hardened steel band to coact with the slitter wheel. This requires that the sheet of tympan packing has to be cut into strips arranged on each side of such slitter band or bands. 'Y In some instances the known slitters are arranged to slit the sheets after they have been released by the cylinder grippers and while they are being conveyed to a delivery pile support by a series of sheet delivery grippers. Such practice also has its drawbacks because it is exceedingly diicult to control the sheet, the trailing portion of which utters and oats as it is being conveyed and, therefore it is virtually impossible to obtain a satisfactory, straight slit.

It is one of the primary objects of this invention to incorporate in a sheet fed rotary printing press, a slitter which-coacts with a slitting drum built into the press assembly and against which the sheets are slit after the impressionV thereon has been completed, and while they are still held and positively controlled bythe sheet grip pers of such drum.

A further salient object of the invention resides inthe provision of means associated with the sheet delivery mechanism whereby the sheets to be slit are maintained under positive control in proper slitting register untill the slitting operation is completed. l

Another object is to provide means, associated with the slitter, for positively controlling the sheets until the impression thereon is completed and for thereafter presenting them printed side up, to the slitter.

A still furtherV object is to provide a sheet slitting device which can be adjusted to accommodate cutting wheels of various diameters.

Another object is to provide means for adjusting the contact pressure of the cutting wheel With the slitting drum with micrometer precision,

A further object of this invention is to provide a slitting device which will be eiiicient in operation, extremely rigid in construction and economical to manufacture.

Other objects and distinct advantages of this invention will become apparent from the following specification when read in conjunction with the accompanying drawings which disclose a preferred embodiment of the invention and wherein:

Figure l is a schematic view in side elevation of a printing press embodying this invention.

Figure 2 is an enlarged plan view of the slitter head, its adjusting means, and its associated drum.

Figure 3 is a sectional view taken along line III- III of Figure 2.

Figure 4 is an enlarged sectional view along line lV-IV of Figure 2, and,

Figure 5 is an enlarged side view of the slitter adjusting mechanism taken along line V-V of Figure 2.

Figure 6 is a longitudinal cross section taken through the slitting drum and showing a plurality of drum sections and steel inserts or slitting rings, and

Figure 7 is a partial cross section illustrating means. whereby the chain delivery mechanism is prevented from lateral movement during the slitting operation.

Referring now to Figure l of the drawings, it will be seen that this invention is disclosed, merely by way of example, as embodied in a conventional sheet fed rotary lithographie printing press. In such presses, the printing couple comprises a plate cylinder 10, a blanket cylinder 11 and an impression cylinder 12, al1 of said cylinders being journalled for rotation in side frame members 13. The sheets to be printed are fed over a feed table 14 to conventional transfer grippers indicated at 16 which grip, accelerate, and transfer the sheets to grippers provided on the impression cylinder 12 to receive a printing image from the blanket cylinder 11 which is substantially the same diameter as the impression cylinder.

By means of the grippers on the transfer drum 17, the sheet is withdrawn from the impression cylinder underl positive control and steady, even tension until the impression is completed on the trailing portion of the sheet to thereby assure perfect register of the printing impressions over the full length of the sheet. From the. drum 17 the sheet is then transferred to a slitter drum' 18, also of substantially the same diameter, where it is slit into any desired number of sections and transferred to delivery grippers 8, carried by chains 9, which pass around sprockets located at each end of a conventional delivery reel indicated generally as 19 and which grippers convey the sheets, or the several sections, to a delivery pile 20. The position of consecutive sheets is indicated by dotted lines in Figure l and it will be noted that the trailing portion of a sheet is controlled by the drums 17 and 18 as it passes therebetween during the slitting operation. f

Heretofore, in presses of the sheet fed, rotary class, the sheets were transferred from the impression cylinder directly to the delivery chain grippers, and in most instances the slitter was adapted to coact against the impression cylinder surface whereby the slitting and/or delivering of the sheets commenced before the sheets were completely printed. lt was found by actual test, that under such conditions, the sheets were stripped off the impression cylinder under tension which varied across the width of the sheets, and that stresses were induced in the sheets by the action of the slitter cr by the sheet delivery conveyor. As a result, the register of the impressions on the trailing portion of the sheets was invariably defective.

This condition was found to be especially noticable on rotary sheet fed letterpresses because the printing plates used on such presses are not always evenly distrib uted over the entire surface of the plate cylinder and, as a result, the tension on the sheet is not uniform as it is being stripped off the impression cylinder by the grippers of a sheet conveyor such as a chain delivery. However, by inserting the full size, transfer drum 17 and the equal size slitter drum 18 between the impression cylinder 12 and the delivery reel 19 of substantially the same diameter, the sheet can be removed from the impression cylinder under tension which is equalized across its entire width and the impression can be completed on the trailing portion thereof before the grippers on the transfer drum 17 transfer its leading edge to the grippers on the slitter drum 18, and before actual slitting thereof commences. Furthermore, the sheets will be controlled and maintained in slitting registration during the entire slitting operation.

In addition, drum 17 also enables the sheet to be presented to the slitter drum 18 with its printed side up to prevent offsetting of the freshly deposited ink onto the surface of drum 18.

The slitter drum 18, see Figures 1, 2, 3, and 6, is also journalled in the side frames 13 and is preferably formed of two r more cylindrical sections 21 between which are arranged the discs 22 which are provided about their periphery with hardened steel rings 23. These rings afford a continuous hardened surface to coact with the cutting wheel when slitting sheets, and are located in predetermined positions axially of the drum.

When sheets are to be slit along lines which do not coincide with the rings 23, an auxiliary hardened steel band 24 is used. See Figures 2 and 3. This band may be located in any desired position axially on the drum 18 and its ends are secured in position on the bracket 25, mounted on the shaft 26 within the gap 27 of the drum 18. As shown in Figure 3, bracket is provided with an arcuate arm 28 which spans the greater portion of the gap 27 and acts as a backing for the flexible band 24 against the pressure of the cutting wheel 29 as it passes over the gap 27.

The slitter drum 18 is also provided with sheet grippers 30 which maintain the leading edge of the sheet securely in register while it is being slit and until it is transferred to the grippers of the chain delivery. An air brush, preferably in the form of an air blast tube 31, Figures 2 and 3, is also provided adjacent the slitter drum 18 and immediately forward of the cutting wheel for applying a blast of air onto the trailing portion of the sheet along its entire width to thereby hold it flat against the drum 18 and prevent buckling or twisting of the sheet while it is being slit.

The cutting wheel assembly, as best shown in Figures 2, 3, and 4, comprises the cutting wheel 29 which is rotatably mounted on shaft 32 between the parallel faces of the bifurcated arm 33 of bell crank lever 34 which is p ivoted at 3S between the projecting parallel side walls 36 and 37 of bracket 38. An arm 39 of bell crank 34 projects upwardly between the side walls 36 and 37 and is formed with a recess 40 in which one end of compression spring 41 is seated. The free end of spring 41 projects into an opening 42 provided therefor in the bracket 38 and it is retained in said opening by means of the threaded plug 43 whereby the pressure of the spring against the arm 39 and therewith of the cutting wheel 29 against the material to be slit, can be adjusted. When first assembled, plug 43 is adjusted to thereby preload spring 41 so that a pre-determined pressure is exerted against arm 39 after which plug 43 is set against further movement by any preferred conventional means.

immediately forward of the arm 39 and rigidly secured to the side walls 36 and 37, is a cross member 44 in which is slidably mounted a stud 45 with its head 46 adjacent a machined face provided on the arm 39. Stud 45 is locked in its adjusted position preferably by means of a set screw 47.

The purpose of stud 4S is to limit the clockwise movement of bell crank 34 and therewith of the cutting wheel 29 as the latter passes the gap 27 in drum 18 when slitting is accomplished against the auxiliary band 24, as will be xplained more fully hereinafter.

The cutting wheel supporting bracket 38 is clamped in position by any conventional means, such as by the bolts 48 and key 49, on a transverse shaft 51 which is arranged parallel to the axis of the slitter drum 18, and has its ends journalled for rotation in the side frame members 13 of the press. It will be apparent, therefore, that the bracket 38 and therewith the cutting wheel assembly may be adjusted to any location axially of the drum 18 by loosening bolts 48 and sliding the bracket axially on the shaft 51.

Rigidly secured to one end of shaft 51 and preferably on the feeder side of the press, is a lever 52 by means of which the pressure of the cutting wheel 29 against the steel rings 23 and/or steel band 24 on the drum 18 is controlled. See Figures 2 and 5. The lever 52 projects substantially horizontally from shaft 51 and midway of its length it is provided with the rotatably mounted stud 53 which is drilled and tapped to receive an adjusting screw 54.

The depending end of said screw is rotatably inserted in the pivot pin 57 which in turn is rockably mounted in a bracket 58 fixed to the press frame member 13. A collar 59 is pinned to the projecting end of screw 54 to hold it in position in the pin 57 and prevent any vertical movement thereof.

At the upper or free end of screw 54 is a handwheel 61 by means of which the screw is rotated to either raise or lower the lever 52, which motion in turn rocks the shaft 51 either clockwise or counter-clockwise to vary the pressure of the cutting wheel 29 with respect to the drum 18. The screw 54 may also be adjusted to thereby raise the cutting wheel 29 to an inoperative position as indicated by the broken lines in Figure 3. The adjusting screw S4 is locked against unintended movement, after adjustments have been completed, by means of the thumb screw 62, see Figure 2, which is threaded into the end of stud 53 for engagement with screw 54.

At the free end of lever 52 is an adjustable stop member 63, see Figure 5, which is set with relation to the diameter of the cutting wheel being used and which is clamped in position by a bolt 64.

The pressure of the cutting wheel 29 on the drum 18 is regulated with micrometer precision by means of the calibrated pressure screw 66 which is adjustably mounted in a bracket 67 fixed to the press frame member 13 and which is arranged to engage the head of the stop member 63 whereby the extent of movement of lever 52 is determined. The pressure limiting screw 66 has an elongated head 68 which is provided with axially aligned grooves 69 at 90 intervals about its periphery and a spring urged ball 71 is arranged to successively engage the grooves 69 as'the screw 66 is being turned for adjustment.

The screw 66 is calibrated with direct relation tothe 5 Spring 41 so that any angular displacement of screw 66 will effect a pre-determined change in the pressure of the cutting wheel 29 against the drum 18. For'example, a quarter turn of the screw 66, i. e. from one groove 69 to the next, in either direction, will vary the pressure of the cutting wheel against 4the drum a definite amount for instance 5 pounds.

As a result, the cutting wheel pressure can be readily ascertained at any time while the press is in operation. Moreover, it may be varied accurately and efficiently to any desired degree of pressure Within the limits of the device by turning screw 66 through the required number of increments.

The. screw 66 is also provided with a collar 72 which limits its upward movements and thereby determines the maximum pressure of the cutting wheel 29 against the drum 18.

After the leading edge of a sheet passes beneath the cutting wheel 29, it is transferred to the chain delivery grippers 8 which thereafter maintain control of the sheet until it is completely severed and then convey the slit sections to the delivery pile 20.

In order that the slitting of the tail end of the sheet will be straight and without any distortion, the sprockets 75, see Figure 7, one of which is provided at each end of the delivery reel 19 to drive the delivery chains 9, are adjusted axially on their supporting shaft 76 until they engage the inner surface of the outer links of the chain 9. As a result, the lateral movement of the chains and therewith the delivery grippers is reduced to a minimum and the alignment of the sheet will be maintained as its leading edge is transferred from the grippers 30 of the slitter drum to the grippers 8 of the delivery conveyor.

In addition, tracks 78, see Figures 1 and 7, are provided above and below the chains to guide them through their endless path. These tracks are supported on the side frame members and are positioned so that they are also adjacent the outer links of the chains to thereby maintain the alignment of the delivery grippers after they leave the sprockets 75 and until the trailing portion of the sheet has been slit. The sprockets and tracks are positioned at the time of assembly of the press and no further adjustments are necessary.

The procedure for setting the slitter mechanism is as follows:

When the sheets or web are to be slit on the center line, for example, bolts 48 in bracket 38 are loosened and the bracket adjusted axially on shaft 51 to bring the cutting edge of wheel 29 in line with the location of the slit. Bolts 48 are then tightened to lock the bracket 38 against any unintended axial movement.

With the stop member 63 and the pressure regulating screw 66 in their lowermost position and with thumb screw 62 backed oif, handwheel 61 is rotated to raise lever 52 and thereby rock the shaft 51 until the cutting wheel 29 contacts the periphery, i. e. the steel ring 23 of drum 1S. Then the stop member 63 is raised until it contacts screw 66 after which it is locked in position by tightening the bolt 64.

With the parts so set, the cutting wheel is merely contacting the ring 23 and is not under operative pressure. Therefore, the next step is to apply pressure to the cutting wheel to an extent that will be suicient to slit the material being processed, but not to a degree that it will cause premature Wear of the cutting edge. The extent of pressure necessary is dependent, of course, upon the quality and thickness of the material to be slit and in most instances, the pressure will have to be varied at the start of a job until the proper setting is arrived at.

The extent of pressure applied to the cutting wheel 29 is accurately controlled by adjusting the regulating screw 66 through the necessary number of increments, i. e. grooves 69, until the desired pressure is indicated. Handwheel 61 is then rotated to raise lever 52 which action rocks the shaft 51 clockwise causing the bell crank lever 3,4 't: pivot'counterclockwise and its a`rm`39 to compress Spr1n'g'41. This movement continues until stop member 63 lagain contacts screw 66 at which time thumbscrew 62 ist tightened to lock the screw 54 against further movemen v VWhen making the slit on any of the steel rings 23 of the 4drum 18, no further adjustment of the slitter assembly is necessary because the rings 23 present an endless track on which the cutting wheel 29 travels. However, when the location of the slit does not coincide with any of the rings 23 and the slitting is to be done oriV the auxiliary band 24, it is necessary to control the clockwise movement of bell crank 34 and therewith wheel 29- as it passes the gap 27 on the drum 18. As shown in'Figure 3, the ends of the band 24 are located within the periphery of said drum and fastened in the gap 27 on the bracket 25. Therefore, unless the clockwisemovement of the bell crank 34 is controlled in order to maintain the cutting edge of the wheel 29 substantially tangent to the periphery of the drum 18 as it passes over the gap, it will dip into `the gap, due to the pressure of spring 41 on arm 39, and strike the heads of the band retaining screws. This would result in severe shocks and damage to the wheel, as well as to the band 24.

vWhen, as indicated herein, sheets are to be slit on the auxiliary band, then the movement of the bell crank 34 is controlled by means of the stud 45, see Figure 4. After the wheel 29 is set to the required pressure against the drum 18, i. e. band 24, the set screw 47 is backed ol and the stud 45 is moved inwardly until its head 46 has but a slight clearance with respect to the machined face on the arm 39. The set screw 47 is then tightened to lock the stud 45 in position. Consequently, as the wheel 29 passes over the gap 27, the clockwise movement of bell crank 34 will be limited to a very small extent so that the wheel 29 will remain substantially tangent tothe periphery of the drum 18 until it again engages the band 24.

It will be understood that the embodiment of the invention herein disclosed is merely by way of example and that modications in the construction and arrangement of parts may be made without departing from the spirit and essence of the invention as represented by the appended claims.

We claim:

1. In asheet fed rotary printing press having an impression cylinder, the combination comprising, a first cylinder having gripper elements thereon for taking printed sheets from the impression cylinder, a second cylinder having gripper elements to which the sheets are conveyed by said lirst cylinder, sheet slitting means adapted to co-act with the cylindrical surface of said second cylinder for slitting sheets carried thereby, said cylinders being adapted to carry the sheets completely past the point of impression before they are engaged by the slitting means, and sheet delivery means including a delivery reel and a chain conveyor having gripper elements for transferring the slit sheets from said second cylinder to a pile support, said trst and second cylinders and the delivery reel having diameters substantially equal to the diameter of the impression cylinder and being arranged in a substantially horizontal plane below and forward with respect to the axis of the impression cylinder.

2. In a machine of the class described, an impression cylinder, a sheet delivery conveyor, a plurality of sheet transfer drums each having gripper elements thereon and having operation to transfer sheets of material sequentially from said impression cylinder to the delivery conveyor, a slitter unit including a cutting wheel having an operative position wherein it coacts with the cylindrical surface of one of said drums for slitting sheets while they are held by the gripper elements on said drum, supporting means for said wheel including resilient spring means for urging said cutting wheel against the periphery of said drum, a manually operable lever connected with said supporting means and operable from a remote position at one side of the machine for varying the tension of said spring means while the machine is in operation to thereby vary the pressure of said wheel on said drum while said wheel is in its operative position, and an adjustable stop member having coaction with said lever to define the ex tent of adjustment imparted thereto, said stop member being calibrated with relation `to said spring means whereby the pressure of said wheel on said drum can be accurately regulated and readily ascertained.

3. In combination with a rotary, sheet fed printing press, a slitter drum having sheet engaging elements, a slitter associated with said drum, an impression cylinder, a sheet transfer drum having grippers arranged to transfer printed sheets directly from the impression cylinder to said elements in a curvilinear path whereby vprinting of the sheet is completed before its leading edge is engaged by the slitter, the cylindrical surfaces of said transfer drum and slitter drum coacting to control the trailing portion of said sheet while it is being slit', air blast rnean's mounted immediately forward of said slitter and having operation in conjunction with said drums to control the trailing portion of the sheet, a delivery reel, and a lchain conveyor associated with said reel, for delivering the slit sheets from the press.

4. A slitting mechanism for a sheet fed rotary printing press comprising, a slitter drum, a rotatable shaft mounted above and parallel with said drum, a supporting member fixed to said shaft, a bracket pivotally mounted on said supporting member, a rotary cutting wheel carried by said bracket for eoaction with the cylindrical surface of said drum, resilient spring means interposed between the supporting member and said bracket for urging the cutting wheel into contact with said surface, means Vfor adjusting the angular position of said shaft and thereby the pressure of said wheel on said surface including a lever fixed to the end of said shaft and operable from one side of the printing press, a stop member calibrated with relation to said spring means and adjustable to define the angular position of said lever and thereby the pressure of the cutting wheel on said surface, and screw means threadedly engaging said lever for adjusting the lever relative to said stop member.

5, A sheet delivery mechanism for conveying printed sheets from the impression cylinder of a printing press to a delivery pile comprising, a sheet transfer drum equal in size to and mounted for rotation adjacent said impression cylinder, grippers on said transfer drum for taking the sheets from the impression cylinder under uniform tension, an equal size slitter drum mounted for rotation adjacent said transfer drum and having grippers for taking the sheets from the transfer drum, said drums being mounted below 4and forward with respect to the impression cylinder, sheet slitting means including a `cutting wheel arranged to coact with the cylindrical surface of the slitter drum to slit the sheets while they are carried thereby, said drums being adapted to carry the sheets in a curvilinear path whereby the impression is completed on each sheet before its leading edge engages said cutting wheel, spring means for urging the cutting wheel against said cylindrical surface, means located at one side of the press and including a member calibrated with relation to said spring means for effecting predetermined adjustments of the pressure between the cutting wheel and said surface while the press is in operation, and an endless sheet conveyor having grippers for conveying the slit sheets from the slitter drum to the delivery pile.

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